"I came to the Messenger of Allah while he was riding, and I put my hand on his foot and said: 'Teach me Surah Hud, teach me Surah Yusuf. He said: 'You will never recite anything more precious before Allah, the Mighty and Sublime, than: 'Say: I seek refuge with (Allah) the Lord of the daybreak.'"
Sunan an-Nasa'i Book 50, Hadith 12